1. Field of the Invention
This invention relates to a toolholder for use in a rotary crop-cutting machine, such as a mowing or chopping machine, which toolholder comprises a rotatable tool carrier, to which the tools are adapted to be pivoted on pins, which are parallel to the axis of rotation of the tool carrier, wherein each of said pins carries at least one tool and at opposite ends is radially slidably mounted in axially aligned slots, which extend radially with respect to the axis of rotation and are formed in two axially spaced apart lugs, which are secured to and substantially radially protrude from the body of the tool carrier, or in two axially spaced apart disks, which constitute the tool carrier, and wherein each of said slots has a radially outer portion for retaining the associated pin against axial displacement in said radially outer portion.
2. Description of the Prior Art
Because the tools are pivotally movable, they can yield when they strike against a hard object, such as a stone, during the rotation of the tool carrier so that substantial damage to the tools will be prevented. Obviously the pins are radially slidable in the slots so that under the action of centrifugal force the pins will move to the radially outer end of the slots, where they are retained against an axial displacement so that they cannot move out of the slots. When it is desired to remove said pins or the tools it will be sufficient to shift the pins and tools to the radially inner end of the slots while the tool carrier is stationary and at said radially inner end the pins will no longer be retained against an axial displacement so that the pins can then be removed. In such toolholders the tools cannot be mounted and removed without an auxiliary implement.
Such a toolholder is known from EP-A1 0 395 624 and has proved satisfactory. In order to ensure that the pins will be retained against an axial displacement in the radially outer portion of the slots, that portion of the slots is covered by sheet metal elements, which are welded to the lugs or to the disks which constitute the tool carrier. Such sheet metal elements add to the expenditure of material and result in an often undesirable increase of the size of the toolholder in the axial direction. Besides, the lugs or disks must be rather thick so that the pin end portions can extend into the slots to a sufficient depth. If the lugs or disks are relatively thin, those portions of the axially spaced apart lugs or disks which are formed with the slots may move apart adjacent to the radially outer ends of the slots so that the pin ends can enter the slots only to a small depth and may move out of the slots and just as the tools may be thrown off by centrifugal force and may then endanger or injure or damage human beings or machines. It will be understood that the use of thick lugs or disks will increase the size of the toolholder in the axial dimension.
From French Patent Specification No. 1,520,653 it is also known that the pins may be fixed to a tool carrier so that the pins protrude upwardly. In that case the tools have circular holes, with which they are fitted on the pins, and are then retained by means of locking bars, which are formed with key-holelike apertures so that the pin ends can first be inserted into the wider portion of the apertures and the bars may then be displaced to a position in which the narrow portion of the apertures is received by a groove formed in the pin end portion. By a central screw the locking bars are then fixed to the tool carrier in that position for locking the tools in the use of that arrangement an implement is required for fixing the tools and for an exchange of tools because the central screw cannot be tightened and loosened without an implement.
In another known design (Published German Application 29 20 244), leaf springs are secured to the underside of a knife-carrying disk and are also formed with a keyholelike aperture for retaining a pivot pin for a knife. The pivot pin is inserted into the wider portion of the aperture and is then displaced toward the narrower portion, in which the edges of the aperture enter a groove in the pin so that the latter is retained. A separate plate is riveted to the leaf spring and serves to lock the pin in that position so that it is difficult to replace a pin. The knife is a friction fit on the pin and an axial displacement of the knife on the pin is prevented in that the leaf spring urges the knife against the underside of the knife-carrying disk. That design also involves a considerable structural expenditure and does not permit a change of a tool without the use of an implement because the leaf spring must be forced away from the knife-carrying disk before the knife can be removed or replaced.